Just about everything humans do requires their sense of vision. Since the human eye reacts to the visible wavelengths, sources of light, such as the light from the sun and artificial lighting, are required, since the ability to see an object requires that light be reflected off of such object towards the eyes of a human.
Further, there are many applications where a desired light color, or wavelength, is needed or desired for a particular application. For example, it is often desired to have various colored lights for entertainment applications, such as within music concerts or stage plays. On another end of the application spectrum, particular light wavelengths are needed in blood analyzers. What is evident in all such applications is that a desired spectrum of light needs to be created. It would further be desirable to have a light source that is tunable so that a plurality of light wavelengths can be alternatively projected.